Process for treating ores and metallurgical products, slags, and the like



atented Ar. 8, 193

PI CE FRIEDRIGHLJOHANNSEN, OFMAGDEBURG, GERMANY, Assrenoa To run FIRMFRIED, KRUPP GnusoNwEnK AK'rmNensnLLsoHArr, or MAGDEBURG-IBUCKAU,GERMANY PROGESS FOR TREATING ORES AND METALLURGICAL PRODUCTS,SLAGS,'.AND THE LIKE 4 r Ho Drawing. Application filed October 14, 1926,Serial No. 141,675, and in Germany November 5, 1925.

This invention relates to a process for treating ores and metallurgicalproducts, slags and the like, which contain volatilizable metals such aszinc, tin, lead, antimony,

5 arsenic, quick-silver and bismuth, which can be recovered in the formof metal fumes. By the known processes in this art, the ore and the.like, together with reduction material or other materials serving forvolatilization of mthe metals are fed into ametallurgical furnace, forexample a rotary kiln, continuously or intermittently, and heated whilethe materialgoes through the furnace. The metals liberated by the effectof the heat and reduction,materials are volatilized and oxidized withthe formation of oxides or other comfl tion or volatilization zone asufiiciently high temperature, for example, for zinc-containingmaterials 1000 to 1300 Cl, in order thatthe chemical separation of thevolatile metals out of the charging material by means of the reducing aents and the like may take placewith.suific1ent rapidity andcompleteness. There are, however, ores and other materials which becauseof their composition and chemical properties melt easily. If one chargesan easily fusible material in the usual way together with reduction orfuel material in the preliminary zone, that is, between the entrance endand the reduction zone of the furnace, there is produced because ,of thecombustion 'of the fuel in the oxidizing atmosphere so high atemperature that the charge according to its chemical pi'operties eitherbecomes fluid, orat least at the-entry into the hot reduction zone goesover into the fluid condition. This has the disadvans tage that thereductionand volatilization proceed incompletely and besides, thespecifically lighter combustion material rises to most part uselesslyburned. This can occur,

the surface of the fluid charge and is for the as above pointed out,with certain especially easily meltable ores or other materials, even inthe preliminary zone.

The essential of this invention .consists therein that by special meanswhich are further described. below,-the meltingis preventthe process areadded after or during the en- .trance of the charge into the reductionand vaporization zone and thereby mixed with,

the charge. By the addition of reducing or combustion material in thereaction zone, the melting is prevented or lessened for a variety ofreasons. If one uses non-volatile combustion material (e. g. coke oranthracite), the

infusible carbon acts as a stiffening material. Still more efiective isthe use of raw combustible material containing gases. This is im-'mediately decomposed, and releases distillation gases. This procedurerequires heat which is drawn out of the charge. The re suiting gaseshave also tiine to burn in the furnace chamber between the reaction zoneand the exit openin so that a contamination of the metallic oxi asrecovered by tar vapors and the like is avoided. The cooling efiect ofthe combustion material can be still further increased if itis-introduced into the chamber in a moist conditiom B the vapo rizationof water, still further eat is absorbed and thereby the desiredprevention of other materials which by their quicker .eifect A onthecharge produce combinations of higher melting point. Lime orlimestone is such a material. Depending upon the composition of thecharge, there can also be used other materials such as clay or othersilicates, silica, etc. s

U 111 some cases is it desirable to introduce into'the reactionszone orewhich when of suitable composition, can,.-just as in the case vent orreduce the melting of lime, make an easily fusible charge morediflicultly fusible. The ore introduced into the easily fusible chargein the reaction zone envelops the char e and also serves to produce acooling e ect, since there occurs a vigorous reducing action on themineral or metal substances in the ore. This reaction is endothermic incharacter 'and heat is absorbed which otherwise would be active inmelting the charge; Ifthe ore introduced into the reaction zone isentirely or in part finely'granular, the further advanta e is obtainedthat a contamination of the oxide tobe recovered by any fine ore dustcarried therewith is largely avoided. I

Further, the manner of introduction of the fuel and other materials, andthe manner and rapidity of themixing in the char e can preof t e charge.The fuel can be introduced from the back or the front end of thefurnace, according to themethods used in powdered dust firing.

The fuel, etc., can also be introduced through the walls of the furnaceby any suitable arrangements of the well known art of charging, and atany desired place. Any one or more of these methods can besimultaneously used.

Byregulation of the pressure of the carrying gases (air, steam, etc.)and by varying the shape of the tuyere nozzle to produce more or lessspreading of the material introduced, wide variations in the regulationof the introduced materials can be effected.

vIt will be understood thatin a furnace, such as a rotary kiln, thecharge as it pro-. gresses through the kiln is graually heated up to thehi h temperature necessary for volatilization. .This portion reductionan of the furnace has been called the preliminary zone.

When the charge of ore and reduc ing material reaches the reducin orreaction zone it is subjected to such big temperatures that it ma beactually fused, which is undesiris continuously agitated, progressivelyheating the charge in an oxidizing atmos here to a temperature at, whichthe volatihzable metals will be reduced and va orized, delivering thematerials requisite or thecompletion of the reduction and vaporizationof the metals wholl or in part into this highly heated portion 0 thefurnace where the zone of reaction be ins where they are continuouslymixed with the charge thereby reducing and volatilizing thevolatilizable metals, and immediatel oxidizing the metallic vapors soproduce the conditions being so controlled that fusion. of the charge inthe reduction'z'one is prevented.

2. Process according; to claim 1, characterized thereby that t ematerials required for the volatilization are added wholly ,or in partin the form of raw fuel such as stone coal, round coal, whereby thegaseous products ormed therefrom separate on their en'- trance into thehot zone and are burned within the furnace, While the entirely or onlpartially degasified fuel is mixed wit charge as a reduction agent. 3.Process according to claim 1, characable, cause there is less ready andcomplete liberation of the vaporized metals from a fused mass than froman unfused mass'of continuously agitated ore and reductionmachemicalcompounds from which the metal is volatilized only withdifliculty, is prevented. The fusion of the charge in the reaction zoneis prevented or corrected by the various methods above described. r

This application is .a continuation'in part No. 7 9,246, filed January4, 1926. 1

I claim:

:5 es and me 'allu-rgic'al products-which conjta volatiliz blc metalswhich consists in "f' githechar'ge into a rotary'furnace progresses andin which it the

